DK181136B1

DK181136B1 - Apparatus, method and use for comminuting green leaved biomass

Info

Publication number: DK181136B1
Application number: DKPA202100430A
Authority: DK
Inventors: Schønfeldt Henrik; Simonsen Steen
Original assignee: Stecao Aps
Priority date: 2021-04-29
Filing date: 2021-04-29
Publication date: 2023-02-15
Also published as: DK202100430A1; WO2022229336A1

Abstract

The present invention relates to an apparatus for manufacturing a protein product from green leaved biomass such as grass, clover, alfalfa. In particular, the invention relates to an initial or first part of a process where the green leaved biomass is treated to become a green juice. Also, the present invention relates to a process for producing protein by application of the apparatus. In particular, the invention relates to an apparatus for comminuting green leaved biomass comprising a drum (1) inside a housing (3), which drum (1) is rotated by a drive shaft (2), the housing (3) provides a space around the rotating drum (1) and has an inlet (4) for biomass, an outlet (5) for a product, which housing (3) comprises a second outlet (6) for a product fraction comprising longer fibres.

Description

Apparatus, method and use for comminuting green leaved biomass

The present invention relates to an apparatus for manufacturing a protein product from green leaved biomass such as grass, clover, alfalfa. In particular, the invention relates to an initial or first part of a process where the green leaved biomass is treated to become a green juice.

Also, the present invention relates to a process for producing protein by application of the apparatus.

Background of the invention

Normally, protein from green leaved biomass is prepared from harvested plant material by squeezing the plant material e.g. in a screw press.

WO 2015/197078 relates to a method for providing a leaf protein feed concentrate comprising the steps of: (i) pressing a green plant material, (ii) obtaining a press cake and a green juice (iii) optionally subjecting said green juice to UHT Sterilization/pasteurization and obtaining a sterilized/pasteurized green juice (iv) subjecting the green juice or sterilized green juice to lactic acid fermentation followed by separation, (v) obtaining a leaf protein feed concentrate and a brown juice.

According to this document the plant material comprises a protein content in the range from 0.1 to 6% (w/w) and the green juice has a protein content in the range of 0.1 to 15% (w/w)

US 4,359,530 A discloses a method of extracting protein from green leaved crops or biomasses such as leaves, grasses, legumes, stems of green plants and tree leaves. The method comprises the steps of subjecting the green leaved biomass to a pulping action in an acid solution recirculated from a subsequent anaerobic fermentation step to produce a pulp comprising a protein-rich liquid and fibrous material. The protein-rich liquid in the pulp is separated from the fibrous material. The protein is separated from the protein-rich liquid by anaerobic fermentation in an acidic solution thereby providing a concentrated protein fraction suitable for preservation and an acidic solution at least a portion of which is recycled to insure further removal of protein from the fibrous material.

When the green leaved biomass is subject to pressing or hammering as a first step to separate fibres from protein containing juice, the proteins may be partly destroyed which results in a lower yield of dried protein pr kilogram green leaved biomass or in a lower quality of the obtained dried protein.

EP 1239740 Al discloses a method for continuous separation of vegetable biomass into a fluid phase and a solid containing phase of pulpy consistence. According to this method, moist vegetable biomass (21) is fed (22, 24) to a mixing zone (26) equipped with stirring means

(27) of a conditioning vessel (25). Aqueous juice (30) recycled (40) from a subsequent step (39) is also fed (29) to the mixing zone (26). The mixture is fed (32) to a processing apparatus (33) whose operation involves the generation of a gradient of flow speed within the flowing suspension, which opens cells of the vegetable biomass to liberate their content into the aqueous juice. The produced slurry (34) is then fed to a separator (35) for partitioning into aqueous juice (36) and mush (37). Le. the first separation takes place in a different apparatus, and the present invention therefore provides a more compact and efficient apparatus.

Summary of the invention

Thus, an object of the present invention relates to provide an apparatus for manufacturing a protein product from green leaved biomass such as grass, clover, alfalfa or the like.

In particular, it is an object of the present invention to provide a process and an apparatus that solves the above-mentioned problems of the prior art by cutting the raw green leaved biomass to a pulp instead of hammering or pressing thereby releasing proteins from the cells without increasing the temperature.

Thus, according to a first aspect the invention relates to an apparatus for preparation of comminuted product from green leaved biomass comprising a drum (1) inside a housing (3), which drum (1) is rotated by a drive shaft (2) and which drum (1) comprises a plurality of knives or blades (8) or other sharp or pointy protrusions extending from the outer surface of the drum (1), the housing (3) provides a space around the rotating drum (1) and has an inlet (4) for biomass, an outlet (5) for a product, wherein the housing (3) comprises a second outlet (6) for a product fraction comprising longer fibres.

According to any embodiments of the first aspect, the inlet (4) for biomass may be placed above the outlet (5) for product, e.g., the inlet (4) may be placed at the upper half of the housing (3) or at the top of the housing (3).

According to any embodiments of the first aspect, the outlet (5) for the product may be placed at or at least near the bottom of the housing (3).

According to any embodiments of the first aspect, the outlet (6) for the solid fraction may be placed above and/or downstream of the outlet (5) for the product, and/or below and upstream of the inlet (4) for biomass.

According to any embodiments of the first aspect, the drum (1) may comprise a plurality of blades (8) or other sharp or pointy protrusions extending in a radial direction from the outer surface of the drum (1).

According to any embodiments of the first aspect, the blades (8) have a cutting edge extending in a direction approximately perpendicular to the surface of the drum (1).

According to any embodiments of the first aspect, the apparatus may comprise internal guiding means (9) positioned around and/or downstream the outlet (6) guiding a solid fraction comprising comminuted fibres-rich biomass through the outlet (6).

According to any embodiments of the first aspect, the internal guiding means (9) may comprise or be constituted of one or more plates guiding the comminuted or disintegrated solid biomass out from the space around the drum (1) and through the outlet (6).

According to a second aspect, the invention relates to a method for separating biomass into a liquid fraction containing water solvable components and a solid fraction containing predominantly fibre and other unsolvable components comprising the following steps: a) subjecting the green leaved biomass to a cutting action in an apparatus as defined in one of the claims 1-8, preparing an intermediate liquid or paste composition comprising solid fibres dispersed in a liquid, optionally a process liquid is added during the cutting action, b) the intermediate liquid or paste composition is subjected to a first separation step where a solid fraction mainly constituted of fibres is separated from a liquid fraction named green juice.

Optionally, coagulated protein is prepared from the green juice by the following steps: c) the green juice is transferred to a storage container from where the green juice is optionally subjected to stirring, optionally a second flow of green juice is returned from step c) to step a) as process liquid, alternatively water may be used as process liquid d) a first flow of green juice is transferred to a second separation step where part of the remaining fibres is separated from the green juice, optionally the green juice may be subjected to a particle separation step e.g. in a cyclone, before entering the second separation step, e) the green juice is then subjected to a protein coagulation step, f) the coagulated protein is subjected to a third separated step where a protein concentrate is separated from a liquid fraction called brown juice e.g. in a decanter, g) the protein concentrate is then dried to prepare a particulate protein product.

According to a third aspect, the invention relates to a use of an apparatus according to the first aspect, to comminute or disintegrate green leaved biomass, or biomass rich in plant fibres, to such a degree that the comminuted or disintegrated material may be separated into at least two fractions, a solid fraction and a liquid fraction.

According to any embodiment of the third aspect, the green leaved biomass may comprise biomass comprises stems and leaves such as grass, or clover, or alfalfa, or alternatively green peas, beans, or green cereal.

According to any embodiment of the third aspect, the green leaved biomass may have a relatively high content of crude fibre, e.g., above 10% or e.g. above 20%.

Brief description of the figures

Figure 1 shows a side view of an embodiment of an apparatus according to the invention.

Figure 2 shows a cut-through view at the line A-A of the embodiment shown in fig. 1.

Figure 3 shows an enlargement of the parts marked B of a release unit and outlet portion shown in fig. 2.

Figure 4 shows an embodiment of a release unit.

Figure 5 illustrates the steps of a complete process in which the apparatus of the invention may be used.

The present invention will now be described in more detail in the following.

Detailed description of the invention Definitions

Prior to discussing the present invention in further details, the following terms and conventions will first be defined:

In general — when these words are used to define a feature it must be understood that the feature(s) can be used according to all embodiments of the invention.

It should be noted that embodiments and features described in the context of one of the aspects or embodiments of the present invention also apply to the other aspects or embodiments of the invention unless it is particularly mentioned that it does not.

An apparatus according to the present invention is particularly suited for comminuting or disintegrating green leaved biomass, or biomass rich in plant fibres, into a solid fraction and a liquid fraction. When entering the apparatus, the biomass is relatively recently harvested and comprises a certain amount of moisture or juice. The biomass may be grass, or clover, or alfalfa, or similar green leaved type biomass, and the biomass may be a single type of biomass or a mixture of several types of plant material. The protein content of a suitable biomass such as grass, clover or alfalfa is normally around 15-20 % protein. Biomass suitable for processing in an apparatus according to the invention may comprise stems and leaves, causing the biomass to have a relatively high content of crude fibre, e.g., above 10% or e.g. above 20%, however, the green leaved biomass may also be green peas, beans, green cereals, or the like.

Figure 1 shows a side view of an embodiment of an apparatus according to the invention, figure 2 shows a cut-through view along the line A-A shown in fig. 1 and figure 3 shows an enlargement of the part shown in the circle B of fig. 2.

DK 181136 B1

The apparatus comprises a drum 1 inside a housing 3 which drum 1 is rotated by a drive shaft 2 attached to a motor 7. The housing 3 provides an isolated space around the drum 1 and has an inlet 4 for biomass, an outlet 5 for a liquid fraction comprising green juice and fine fibres, and an outlet 6 for a solid fraction comprising fibre and green juice. 5 The inlet 4 for biomass is placed at the top of the housing 3 in the shown embodiment and may in general be placed anywhere at the upper half of the housing 3, to allow gravity to help feed the biomass into the housing 3. The outlet 5 for the liquid fraction may be placed at or at least near the bottom of the housing 3 allowing gravity to assist in removing or draining liquid from the space around the drum 1. The outlet 6 for the solid fraction is placed at a side of the housing 3, above and downstream of the outlet 5 for the liquid fraction, and below and upstream of the inlet 4 for biomass. “Downstream” is defined relative to the direction of rotation of the drum 1 as the biomass travels from the inlet 4 in the direction of rotation, the direction of rotation in the embodiment illustrated in the figures is indicated with an arrow in fig. 2.

In general, the outer surface of the drum 1 comprises a plurality of knives or blades 8 or other sharp or pointy protrusions extending from the outer surface of the drum 1, in the following text the “knives or blades 8 or other sharp or pointy protrusions” are referred to as “blades”. According to one embodiment the blades 8 extends in a direction approximately perpendicular to the surface of the drum 1. When the biomass material is cut or disintegrated by blades and not hammered into a pulp, the temperature inside the apparatus does not raise significantly. Both when entering and when leaving the apparatus, the comminuted material has a temperature corresponding to the temperature of the surroundings, e.g. around 15- 25°C. That the temperature inside the apparatus does not raise significantly means that the temperature change from entering the apparatus to leaving the apparatus, is less than 5°C, e.g. less than 2°C, and normally less than 1°C.

The apparatus comprises a plurality of rotating blades 8 which blades 8 may extend in a radial direction from the surface of the drum 1. Further, the cutting edge of the blades 8 may extend in a direction perpendicular or parallel to the axis of rotation. When the cutting edge of the blades 8 extend in a direction parallel to axis of rotation, the blades 8 extend in a direction deviating with 0° from the axis or rotation, when the blades 8 extend in a direction perpendicular to the axis of rotation, the blades 8 extend in a direction deviating with 90° from the axis or rotation. The blades 8 may extend in a direction deviating between 0° to 90°, e.g., the blades 8 may deviate less than 45°, e.g. less than 30° from the direction of rotation.

The blades 8 may extend in the complete width of the drum 1, or each blade 8 may extend in a part of the width of the drum 8.

The blades may be distributed along the circumference of the rotating drum 1. When the blades 8 extend in a direction parallel to axis of rotation, the blades 8 may be evenly distributed and / or the blades 8 may be placed in parallel and e.g. with a distance between them of 1-4 degrees, e.g. there may be between 90 and 360 blades 8 distributed along the

DK 181136 B1 6 circumference of the drum 1, or there may be e.g. between 120 and 280 blades 8 distributed along the circumference of the drum 1.

Downstream of the inlet 4 and upstream of the outlet 5 for the liquid fraction, the apparatus may comprise a contact area where the biomass feed is forced or pushed towards the drum 1 at least during operation. The contact area may comprise a tear block 11 which prevents or slow down the travelling of the feed material in the space around the drum 1, thereby increasing or promoting contact between biomass and the rotating drum 1.

Downstream of the outlet 5 for the liquid fraction and upstream of the inlet 4 for biomass, the apparatus comprises an outlet 6 for a fraction comprising the main part of the solids of the biomass, i.e., more than 50wt%, in particular fibres originating from stems and/or leaves and/or shells,

The apparatus may comprise internal guiding means 9 positioned around, or above (downstream), or in connection with the outlet 6, figure 3 shows an enlargement of an embodiment of such internal guiding means 9. The internal guiding means 9 according to the shown embodiment comprises several protruding parts which protruding parts will catch the fibre-rich or solid fraction of the biomass during operation, prevent the solid fraction from travelling further in the direction of rotation, and guide the solid fraction from the space around the drum 1 and towards the outlet 6. When the at least partly solid biomass passes through the outlet, external guiding means 10 in form of guiding plates will force the flow of biomass in a desired direction, which according to the shown embodiment is downwards.

When the solid material is guided downwards, gravity assists in removing material from the outlet 6 and preventing stoppage of outgoing flow, alternatively, a pump may be mounted for actively removing material in another direction. In a simple form, the internal guiding means 9 may be shaped like a wedge, so that the product is compacted in the direction of rotation of the rotor before it is led away through gates in the guiding means.

According to an embodiment, the distance between the internal guiding means 9 and the drum 1 may be adjusted, normally the distance between the internal guiding means 9 and the outer edge of a blade 8 is between 0.1 mm and 20 mm, e.g. the distance larger than 0.2 mm, or larger than 0.3 mm, or larger than 0.5 mm, or larger than 0.8 mm, or larger than 1 mm, and the distance may be smaller than 18 mm, or smaller than 15 mm, or smaller than 10 mm, or smaller than 5 mm, or smaller than 2 mm, or smaller than 1.5 mm.

After having been removed from the apparatus through the outlet 6, the solid fraction comprising longer fibres and a minor amount of green juice, may be subjected to a separation process where remaining green juice is extracted/obtained and added to the primary liquid fraction obtained through the outlet 5.

Figure 4a, 4b, 4c, 4d and 4e show an embodiment of a suitable insert from different views.

The insert comprises internal guiding means 9 compacting the biomass and guiding the comminuted biomass toward the outlet 6, external guiding means 10 guiding comminuted solid biomass after having the comminuted biomass has passed through the outlet 6 and fastening means 12 used to fasten and optionally to adapt the distance of the insert to the housing 3 and to surface of the drum 1. The fastening means 12 fastening the insert to the housing 3, may comprise or be constituted by one or more openings 12 for a bolt.

Example of process

Fig. 5 illustrates a complete process for preparation of dried protein from a biomass having a relatively high content of fibres according to which process the biomass may be comminuted in an apparatus according to the present application. The process includes steps for separation of solid and liquid fractions and recovering and drying proteins. However, other method steps for separation and recovering of proteins may be suitable to use.

Step 1) Green buffer storage

Harvested biomass may be stored in a facility normally for a short time to allow a continuous feeding of relatively fresh biomass to the process.

The biomass may be cut by a mower during harvesting. However, any harvesting method preserving the juice with the biomass will be suitable. An intermediate storage section may be used after harvesting, but it is preferred to process the biomass as soon after harvesting as possible, and preferably within 24 hours after harvesting, e.g. within 12 hours.

Step 2) Dewatering and compaction

The biomass may be dewatered and compacted prior to cutting. In this step free water is removed from the biomass and optionally the biomass is compacted e.g. by two conveyor belts, an upper and a lower conveyor belt, between which two conveyor belts the biomass is compacted and dewatered. The purpose is to remove external water from the biomass and prepare the biomass for the comminuting step.

Step 3) Cutter/juicer

When leaving the dewatering section, the biomass is transferred to a cutting or comminution apparatus. The apparatus comprises an inlet 4 for biomass facing upwards, a rotating drum 1 to which multiple blades are fixed along the perimeter, and two outlet openings 5 and 6 for respectively a primarily liquid and a primarily solid fraction. During operation, the rotating drum 1 may be rotated by more than 1000 RPM e.g. up to 2000 RPM or e.g. 1700 RPM, causing the biomass to be cut into a pulp without increasing the temperature of the material.

Inside the cutting apparatus, the biomass is processed to a pulp comprising a solid fraction mainly constituted of fibre and a liquid fraction which contain the main part of the proteins released from the biomass.

Extra liquid may be added through the inlet 4 for biomass or through a second inlet to increase the fluidity of the pulp and create a flow through the cutting apparatus. The extra liquid may e.g. by a fraction of the green juice separated from the pulp from the cutting apparatus, or the extra liquid may be clean water or a liquid stream from another part of the process. Optionally, a conduit may guide green juice back to the inlet 4 or the second inlet of the cutting apparatus.

Step 4) Green juice and fine fibre tank

The mixture of green juice and fine fibres may be pumped to a buffer container which buffer container is normally hermetically closed in order to prevent the proteins from deteriorating and to help evening out variation in the flow for subsequent process steps.

The solid fraction exiting the cutting apparatus may be forwarded to a separation and/or washing unit where washing liquid may be added via a conduit. A liquid transport removed with the solid fraction from the cutting apparatus together with the washing liquid may then be added to the liquid fraction leaving the cutting apparatus. The solid fraction comprising fibres may be removed through a second conduit.

A portion of the green juice may be pumped back to the cutting apparatus to provide liquid for the cutting process and the remainder of the green juice is pumped to further processing in a cyclone.

Step 5) Cyclone

Sand and similar solid particles may be removed from the green juice in a cyclone. The cyclone reduces the wear of the sand in the subsequent equipment and also reduces the amount of ash in the protein product.

Step 6) Sieve centrifuge

After the cyclone, the green juice may be sent through a centrifugal sieve, where protein and soluble dry matter are flushed through a fine-mesh net picking up fibres, thus the green juice is separated into washed fibres and juice. The wash water can be either process water, recycled green juice from downstream in the process or brown juice.

The washed fibre from the centrifugal sieve may be transported to and combined with the fibre fraction from the fibre washing/dewatering unit and may then be transported e.g. by a conveyor belt to a storage place.

Step 7), 8) and 9) Skimming

The juice from the centrifugal filter may be pumped via an outlet pump to a skimming tank.

The skimming tank may comprise a discharge pump which carries the green juice through a dosing system enabling dosing of e.g. pH controlling means and CIP liquid.

Step 10) Heat exchanger I

The green juice may be pumped to and through a heat exchanger, preheating the green juice to approx. 60°C at which temperature protein precipitation normally begins.

Step 11) DSI/heating and Step 13) Heat exchanger II

Steam may then be added to the preheated green juice, e.g. approx. 5% steam added via a steam injector thereby heating the green juice from the preheated temperature to around 85°C, which is the temperature at which coagulation and flocculation of the bulk of the protein occurs. Steam addition may improve coagulation and flocculation of the protein as well as shorten the time the protein needs to be heated, which is an advantage for protein stability.

Alternatively, hot water may be used instead of steam.

Also, this step may comprise or include pasteurization or sterilisation of the green juice, however, pasteurization/sterilization of the green juice or the protein concentrate may also take place at a separate downstream process step.

Step 12) Holding tube/precipitation

The heated green juice may then be pumped into a holding cell allowing a lower linear velocity and thus increasing the flocculation of coagulated protein molecules.

Step 14) Decanter

After the holding cell, the juice may be added to a decanter separating coagulated protein and other solid material such as remaining fibres, lipids and minerals/sand from a flow of juice which is now named brown juice, the brown juice mainly consists of water and dissolved carbohydrates. The brown juice may be around 80-85°C when leaving the decanter and may be sent through the warm side of the heat exchanger I and thus act as a preheating medium before it is fed to a slurry tank on site.

The protein concentrate obtained after the decanter normally has a TS of around 45% and approximately 50% of the TS will be protein, and the temperature of the protein concentrate will be around 65°C when leaving the decanter.

Step 15) Spinner type dryer

One or more conveyor belt(s) may transport the wet protein concentrate to a drying unit and provide the opportunity to flash dry or steam flash dry the protein concentrate.

The amount of brown juice will depend on weather conditions, washing water and steam addition.

Control means

A flow meter may measure the flow of green juice and a control valve may control the return flow to cutter unit 4.

The outlet pump from the centrifugal sieve may be fitted with a double filter on the outlet detects any breakthroughs of material on the centrifugal net before any contamination of the product.

All pumps in the wet section may be equipped with frequency control enabling variation in flow and capacity over time.

DK 181136 B1

Ref. no. | Item name 6 | Outlet for fiber-rich fraction (second outlet) 8 Blades (knives), 9 [internal guiding means

Claims

y DK 181136 B1 PATENT CLAIM

1. Device for shredding green leafy biomass, comprising a drum (1) inside a housing (3), where the drum (1) is rotated by a drive shaft (2), and the drum (1) comprises a plurality of knives or blades (8 ) or other sharp or pointed projections which extend from the outer surface of the drum (1), where the housing (3) provides a space around the rotating drum (1) and has an inlet (4) for biomass, an outlet (5) for a product, characterized in that the housing (3) comprises a second outlet (6) for a product fraction which contains longer fibres.

2. Device according to claim 1, where the inlet (4) for biomass is located above the outlet (5) for product, e.g. the inlet (4) is located in the upper half of the housing (3) or in the top of the housing (3), and/or the outlet (5) for the product is located in or at least near the bottom of the housing (3).

3. — Device according to one of the preceding claims, where the outlet (6) for the solid fraction is located above and/or downstream from the outlet (5) for the product and/or below and upstream from the inlet (4) for biomass.

4. — Device according to one of the preceding claims, where the blades (8) extend in a radial direction, i.e. a direction approximately perpendicular to the surface of the drum (1).

5. Device according to one of the preceding claims, where the device comprises internal control means (9) positioned around and/or downstream from the outlet (6), which control finely divided fiber-rich biomass through the outlet (6).

6. Device according to claim 5, where the internal control means (9) comprises one or more plates which control the finely divided or crushed solid biomass out from the space around the drum (1) and through the outlet (6).

DK 181136 B1 12

7. Process for separating biomass into a liquid fraction, which contains water-soluble components, and a solid fraction, which mainly contains fibers and other insoluble components, characterized by including the following steps: a) subjecting the green leafy biomass to a cutting operation in a device according to one of claims 1-6, to produce an intermediate liquid or paste composition which comprises solid fibers dispersed in a liquid, optionally a process liquid is added during the cutting operation, b) the intermediate liquid or paste composition is subjected to a separate - ring stage, where a solid fraction consisting of fibers is separated from a liquid fraction called green juice.

8. Use of a device according to any one of claims 1-6 for comminuting or crushing green leafy biomass or biomass rich in fibers to such an extent that the comminuted or crushed material can be separated into at least two fractions, a solid fraction and a liquid fraction.

9. Use of a device according to claim 8, where the green leafy biomass has a relatively high content of raw fibres, e.g. over 10% or e.g. over 20%.