Method and system for producing fuel from compressed biomass

Abstract

The invention relates to a method for producing fuel from compressed biomass, said method comprising the following: providing biomass; washing the biomass; comminuting, in particular finely comminuting, the biomass; mechanically dewatering the biomass; drying the biomass; and shaping the biomass; wherein at least two streams of dewatering fluid having different compositions are formed during the mechanical dewatering. The invention also relates to a corresponding system (100) for producing fuel from compressed biomass, to the use of biomass stored under pressure, to a computer-readable medium, and to a program element.

Description

[0001] Process and system for producing fuel from pressed biomass

[0002] AREA OF INVENTION

[0003] The present invention relates to a method and a system for producing fuel from pressed biomass. The present invention further relates to a computer-readable medium and a program element.

[0004] BACKGROUND AND STATE OF THE ART

[0005] The production of fuel, for example in the form of pellets or briquettes, from biomass such as green waste or leaves is a well-known process. For example, WO 2004 / 067685 Al describes a process for producing fuel from pressed biomass, in which the biomass undergoes a comminution and a drying process before being pressed into pellets. Further details on the comminution process are described, among others, in DE 10 2008 035 222 Al and DE 10 2008 064 803 B3. The use of a waterjet cutter and washing the biomass has also proven advantageous, as described in DE 10 2012 203 148 B3. For drying, a contact dryer can be used, for example, as described in DE 10 2016 213 956 Al.

[0006] In the manufacturing process, the processed biomass, especially the washed and shredded biomass, is usually subjected to a mechanical dewatering process as an intermediate step. This produces press water, which has traditionally been considered primarily a waste or by-product. This is partly due to the fact that such press water

[0007] AD: SG: mr often contains substances that are problematic for many applications, such as salts like road salt, which is a component of leaves on roads in winter, or organic materials that may be susceptible to microbial decomposition, potentially producing a variety of other undesirable, and possibly odorous, substances. Furthermore, processing press water and making it available for potential applications can be very costly.

[0008] There is therefore still a need for improvements and optimizations in a process for producing fuel from pressed biomass and in a system used or suitable for this purpose.

[0009] TASK OF INVENTION

[0010] One object of the present invention is therefore to provide an improved method and system for producing fuel from pressed biomass, which in particular has an improved utilization of resources such as the press water produced during a mechanical dewatering process, while maintaining a high quality of the fuel produced.

[0011] SUMMARY OF THE INVENTION

[0012] The inventors of the present invention have carried out extensive investigations and have found that this problem can be solved by selectively dividing or separately collecting press water into two or more streams.

[0013] The press water generated during mechanical dewatering is usually an overlooked byproduct. However, it has been shown that under certain conditions (e.g., removal of foreign matter and pollutants, protein content, COD / BOD values, dilution level), it can be reused as a resource for various applications, such as process water, humidification, fertilizer, protein recovery, and / or biogas production. Since each of these applications requires a different optimal composition of the press water, a mechanism has been developed to generate different press waters from the fuel production process. A significant challenge lies in generating these different press waters, some with high proportions of organic materials, without negatively impacting the quality (e.g., calorific value or pollutant load) of the resulting fuel.The inventors discovered that this can be achieved by selectively collecting press water at different points during mechanical dewatering, with these points being specifically suited to the required differences in the composition of the press water. The specific composition of the press water could be largely controlled by process parameters of pellet production. As an example of implementation, a two-stage dewatering process can be cited, in which the first mechanical dewatering stage differs in its operating parameters from those of the second mechanical dewatering stage.

[0014] The present invention relates accordingly to a process for producing fuel from pressed biomass, the process comprising the following steps: providing (for example, including storage) biomass, washing the (provided) biomass, comminution, in particular fine comminution, of the (washed) biomass, mechanical dewatering of the (compressed) biomass, drying of the (mechanically dewatered) biomass, and shaping (optionally including compaction) of the (dried) biomass. The process is characterized in that at least two streams (mass streams) of dewatering fluid (press water) with different compositions are formed (generated, obtained) during mechanical dewatering.

[0015] Furthermore, the present invention relates to a system (arrangement, device) for producing fuel from pressed biomass, in particular for carrying out a process as described herein, wherein the system comprises a storage unit, a washing unit, a comminution device, in particular a fine comminution device, a mechanical dewatering device, a drying device, and a shaping device (optionally including a compaction device). The mechanical dewatering device (or the assembly of mechanical dewatering devices in the case of multiple mechanical dewatering devices) is designed (configured) such that at least two streams (mass streams) of dewatering fluid (press water) with different compositions are formed (generated, obtained).

[0016] Furthermore, the present invention relates to a computer-readable medium on which a computer program is stored, wherein the computer program is configured such that, when executed on a processor, it controls and / or regulates a method and / or a system for producing fuel from compressed biomass as described herein.

[0017] Furthermore, the present invention relates to a program element which, when executed on a processor, controls and / or regulates a method and / or a system for producing fuel from compressed biomass as described herein. Further problems and advantages of embodiments of the present invention will become apparent from the following detailed description and the accompanying figures.

[0018] BRIEF DESCRIPTION OF THE IMAGES

[0019] Figure 1 is a schematic representation of a system for producing fuel from pressed biomass according to an exemplary embodiment.

[0020] Figure 2 is a schematic representation of a system for producing fuel from pressed biomass according to a further exemplary embodiment.

[0021] DETAILED DESCRIPTION OF THE INVENTION

[0022] Further details of the present invention and other embodiments thereof are described below. However, the present invention is not limited to the following detailed description, which merely serves to illustrate the teachings of the invention.

[0023] It should be noted that features described in connection with one exemplary embodiment can be combined with any other exemplary embodiment. In particular, features described in connection with one exemplary embodiment of a method according to the invention can be combined with any other exemplary embodiment of a method according to the invention, as well as with any exemplary embodiment of a system according to the invention, as well as with any exemplary embodiment of a computer-readable medium according to the invention and any exemplary embodiment of a program element according to the invention, and vice versa, unless expressly stated otherwise.When a term is used with an indefinite or definite article, such as "ein," "eine," "eines," "der," "die," and "das" in the singular, this also includes the plural form, and vice versa, unless the context clearly indicates otherwise. The expressions "aufweisen" and "umfassen," as used here, do not only include the meaning of "contain" or "include," but can also mean "consist of" and "essentially consist of."

[0024] Unless explicitly stated otherwise, the terms "at least partially" or "at least a part" as used here can mean at least 1% of it, at least 2% of it, at least 5% of it, at least 10% of it, at least 15% of it, at least 20% of it, at least 25% of it, at least 30% of it, at least 35% of it, at least 40% of it, at least 45% of it, at least 50% of it, at least 55% of it, at least 60% of it, at least 65% of it, at least 70% of it, at least 75% of it, at least 80% of it, at least 85% of it, at least 90% of it, at least 95% of it, at least 98% of it, at least 99% of it, and can also mean 100% of it.

[0025] In a first aspect, the present invention relates to a method for producing fuel from pressed biomass. The fuel from pressed biomass can, in particular, be pellets and / or briquettes.

[0026] For the purposes of this application, "biomass" refers in particular to plant products that can be used to generate heating energy, electrical energy, and as fuels. For the purposes of this application, "pellets" refers in particular to small bodies of compressed material in spherical or cylindrical shape. These can be, in particular, combustible granules used as a heating medium. The typical diameter of pellets is between 6 and 25 mm. Pellets are mostly used in automatically fed combustion systems and pellet stoves, which offer a similar level of convenience to oil or gas heating systems; however, they are also suitable for firing large-scale systems (e.g., thermal power plants, steam boilers, etc.).

[0027] For the purposes of this application, "briquettes" are understood to mean in particular compressed fuel material with a larger size than pellets, for example with a diameter greater than 25 mm.

[0028] The steps of providing, washing, crushing, in particular fine crushing, mechanical dewatering, drying and shaping (including compaction) can in principle be carried out in an analogous manner as in the literature mentioned at the outset.

[0029] In connection with the present invention, it is important that at least two streams (mass streams) of dewatering fluid (press water) with different compositions are formed (generated, obtained) during mechanical dewatering. This can be achieved, for example, by discharging or extracting two or more streams of dewatering fluid at different times and / or at different positions of the mechanical dewatering device used during a single mechanical dewatering step. Additionally or alternatively, at least two mechanical dewatering steps can be carried out successively (serially, sequentially), with at least one stream of dewatering fluid being discharged or extracted in each step. Within the scope of this application, "dewatering fluid" refers to...“Pressed water” refers in particular to the liquid components of the biomass separated during mechanical dewatering (typically by pressing).

[0030] According to an exemplary embodiment, at least a portion of the (provided) biomass is selected from the group consisting of water hyacinths, seagrass, algae, grass clippings, leaves, green waste, and combinations thereof. It has been shown that the type, biological composition, and mechanical form of the biomass components are relevant for determining the ideal pressure in the mechanical dewatering process for generating different press waters—even under the premise of achieving the highest possible calorific value of the resulting fuels. Surprisingly, it has been found that biomass from green waste and / or leaves, particularly seagrass, water hyacinths, algae, and grass clippings, is sufficiently homogeneous in its biological structure to implement the press water differentiation according to the invention with sufficient efficiency, even on an industrial scale.

[0031] According to an exemplary embodiment, at least two streams of dewatering fluid (press water streams) have different viscosities. The stream with the lower viscosity can be used, in particular, to increase the moisture content (humidifying) of the biomass, as explained in more detail below. The different press water streams with different compositions, as described in the invention, allow the generation of a press water stream that exhibits a lower viscosity than the other for a large part of the operating time. This can be explained, for example, by the fact that the salt content influences the viscosity; in particular, a higher salt content normally leads to a higher viscosity. The press water source with the lower viscosity contains fewer impurities and can therefore be pumped with less energy, requires less filtration, and places less strain on pipe systems, pumps, and nozzles.It is therefore very well suited for moistening biomass and / or supplying the water cutter of a washing unit.

[0032] According to an exemplary embodiment, at least one stream of dewatering fluid is used as process water, for humidification, as fertilizer, for protein recovery, and / or for biogas production. It has been shown that the press water obtained during mechanical dewatering can be reused as a resource for various applications under certain conditions (removal of foreign matter and pollutants, protein content, COD / BOD values, degree of dilution). Suitable applications of press water include:

[0033] 1) Use as process water, typically after treatment by filtration, for example for use in water cutters as cutting water

[0034] 2) Use for humidification within the fuel production process itself: Humidification allows for improved removal of foreign matter and pollutants because these substances can be washed out more effectively at a higher moisture level after surface digestion of the biomass.

[0035] 3) Use as fertilizer. With suitable values ​​for the composition of the press water, it can be applied as fertilizer, in particular as liquid fertilizer in forestry, agriculture and / or in horticulture and landscaping.

[0036] 4) Use for protein production and thus return to a nutrient cycle (plant, animal, human).

[0037] 5) Use for biogas production. For this purpose, the press water should have a sufficiently high content of biomaterial to avoid efficiency problems during fermentation.

[0038] For applications 1) - 3), for example, a low content of organic substances in the press water is advantageous, while for applications 4) and 5) a higher content of organic substances in the press water or press water with a higher COD or BOD value is advantageous.

[0039] In the context of this application, "COD" or "COD value" refers to the chemical oxygen demand. As a sum parameter, it is a measure of the total amount of all substances present in water that can be oxidized under certain conditions. It serves to quantify the organic load of a liquid. This indicator, primarily known from wastewater treatment, is also an indicator of a liquid's organic potential for biogas, fermentation, protein production, and biogas processes. The unit is g O₂ per kg of material. The measurement basis is homogenized material.

[0040] In the context of this application, "BOD" or "BOD value" refers to the biochemical oxygen demand. It indicates the amount of oxygen required for the biotic degradation of organic substances present in water under specific conditions and within a specific timeframe. This indicator, primarily known from wastewater treatment, also serves as an indicator of the organic potential of a liquid for biogas, fermentation, protein production, and biogas processes.

[0041] According to an exemplary embodiment, at least one stream of dewatering fluid is used for biogas production, and the average residence time of the dewatering fluid in a biogas plant is less than one week, particularly less than five days, preferably less than three days. The production of press water with specific properties as a byproduct in the fuel production process according to the invention allows, for example, that when obtaining the press water, a mean residence time of less than one week, particularly less than five days, preferably less than three days, can be achieved only after a high degree of cell disruption through high shear forces. This is of great interest for the throughput and / or dimensioning of such a plant. The technical solution for this high degree of cell disruption can be achieved by collecting the press water for this application only at a late stage of the mechanical dewatering process, e.g.,This occurs only shortly before the biomass enters thermal drying. An additional advantage is that the press water originates from already purified biomaterial from the upstream subsystems and is therefore better suited for biogas utilization than ordinary native biomaterial. Processes from paper manufacturing can also be used for biogas production to prevent the beneficial bacteria from being washed away at the high system throughput. One example of such a process is the use of trickling beads and / or trickling filters, which contribute to bacterial retention.

[0042] According to an exemplary embodiment, the biomass (including foreign liquids) has a dry matter content of less than 30%, particularly less than 24%, preferably less than 18%, before the (first) mechanical dewatering. Additionally or alternatively, the biomass can have a dry matter content of less than 45%, particularly less than 38%, preferably less than 32%, before the second mechanical dewatering. With a two-stage mechanical dewatering process, it has been shown that the best operating values ​​are achieved when the first mechanical dewatering reduces the moisture content of the biomass from 85% to 95% to 70% to 75%. In the second stage, ideal operating values ​​for dewatering are from 70% to 75% to 35% to 55%.Conversely, this means that the biomass fed to the first mechanical dewatering process has a dry matter content of less than 30%, in particular less than 24%, preferably less than 18%, and / or that the biomass fed to the second mechanical dewatering process has a dry matter content of less than 45%, in particular less than 38%, preferably less than 32%. If the press water is then collected separately in each mechanical dewatering process and an adapted flow rate is selected, two different press waters are produced.It should be noted that the washing unit and / or the fine grinding process, which leads to a reduction in the COD content after this intermediate stage due to dilution (because of the addition of water in the water cutter and possible moistening in one of the two subsystems), is transformed from a negative effect of dilution into a positive use (2 press waters for different uses) by means of the separated press waters: Press water with a still high COD content can be produced, and another press water with a low COD content and a small proportion of fines is available.

[0043] According to an exemplary embodiment, at least one stream of dewatering fluid has a COD and / or BOD value above 8 g / kg, in particular above 12 g / kg, preferably above 18 g / kg. This stream preferably originates from the final mechanical dewatering stage (dewatering fluid collection point) before (thermal) drying. For press water to be used in a biogas plant, a COD value of 10,000 mg / kg to 20,000 mg / kg of material is required. This press water can then be further concentrated (water evaporation, water vaporization, filtration, etc.) to enable highly efficient biogas operation.

[0044] While the (homogenized) COD value of press water from fresh grass is typically around 60,000 mg / kg, and this value can be increased to 80,000 to 1,000,000 mg / kg by mechanical dewatering, the washing unit and its water input cause significant dilution, so that without the separation according to the invention, the COD value can be below 20,000 mg / kg. The solution according to the invention generates at least one mass flow of dewatering fluid with a COD and / or BOD value of over 8 g / kg, in particular over 12 g / kg, preferably over 18 g / kg, wherein the mass flow originates in particular from the last dewatering fluid collection point before thermal drying.According to an exemplary embodiment, at least two streams of dewatering fluid have different compositions, namely different proportions of foreign matter / impurities, different salt contents, and / or different COD and / or BOD values. By producing two different press water streams according to the invention without impairing fuel quality, different compositions, in particular different proportions of impurities, different salt contents, and / or different COD or BOD values, can be achieved for the two press water streams by means of suitable taps in the press water streams.It should be noted that not only the location of the press water intake is relevant for the described properties and fuel quality, but also the respective conveying speeds of the mechanical dewatering process and the temperatures of the biomass: If the conveying speeds are too slow, depending on the biomass and its temperature, more resins and lignins are released into the press water. While this increases the usable proportion of organic material in the press water, it also alters the calorific value of the produced pellets. This can be achieved through appropriate parameter selection.

[0045] - Pressing force of mechanical drainage

[0046] - Ratio of shear forces to compressive forces in mechanical drainage

[0047] - Temperature of the biomass

[0048] - Moisture level of the supplied biomass

[0049] - Conveyor speed in mechanical dewatering

[0050] - The flow resistance of the press water (which can be increased, for example, by limiting the flow velocity, which in turn changes the quantity and / or composition of the press water) allows the desired differences in the press water to be controlled to a wide extent.

[0051] According to an exemplary embodiment, the process further comprises increasing the moisture content of the biomass prior to the (first) mechanical dewatering, in particular before, during, and / or after the comminution of the biomass. Within the scope of this application, "moisture" or "moisture content" of a biomass is understood to mean not only water or aqueous components, but the entire residue that does not constitute the dry matter (DM) of the biomass. Thus, moisture = 100% minus DM in %. In addition to water or aqueous components, the moisture therefore also includes other fluids such as volatile oil components, etc. The dry matter can be measured in the laboratory. A weighed sample of the mixture is taken and heated to over 100 °C in a drying chamber to evaporate the residual moisture (usually water). The remaining dry residue is weighed and compared to the dry matter content. This yields the dry matter content of the mixture.The liquid that evaporates during this measurement is referred to as the moisture content (in %).

[0052] According to an exemplary embodiment, a first stream of dewatering fluid (press water generated during the initial mechanical dewatering) is used to increase the moisture content of the biomass. Studies have shown that maintaining a high moisture level before the (first) mechanical dewatering is crucial for removing foreign matter and contaminants. To conserve resources, press water with a low foreign matter content can now be added, at least partially, to the biomass to maintain moisture levels without compromising production quality. It is therefore beneficial to use press water, particularly from the initial mechanical dewatering, to moisten the biomass, preferably before, during, or after fine grinding.Adding press water in the vicinity of the fine grinding process allows the temperature increase that the biomass experiences through the addition of press water (due to the mechanical pressing energy supplied during mechanical dewatering) to be maintained throughout the process, thus achieving cost-effective heat recovery. According to an exemplary embodiment, the process further comprises increasing the temperature of the biomass before (thermal) drying, particularly before mechanical dewatering, preferably before, during, and / or after grinding, especially by means of heat recovery. Such heat recovery is based on the heating of the biomass and the press water due to the mechanical energy introduced through mechanical dewatering.The biomass can be heated before fine comminution, in particular before the first mechanical dewatering, preferably before and / or after the second mechanical dewatering, relative to the biomass in the washing unit, whereby this heating can only be carried out using heat exchange or mixing principles and is therefore largely free of primary energy input.

[0053] According to an exemplary embodiment, the difference in COD and / or BOD values ​​is greater than 1000 mg / kg, in particular greater than 2000 mg / kg, and preferably greater than 4000 mg / kg, for at least two dewatering fluid streams. Investigations have shown that, through suitable control of the process parameters according to the invention and a suitable system design, at least two mass flows of dewatering fluids can be generated which exhibit a difference in COD and / or BOD of more than 1000 mg / kg, in particular greater than 2000 mg / kg, and preferably greater than 4000 mg / kg. The measurement parameter can be CODhom (homogenized chemical oxygen demand).

[0054] According to an exemplary embodiment, the mean salt content of at least two streams of dewatering fluid differs by more than 5%, in particular more than 10%, preferably more than 15%. It has also been found that the mean salt content of the two dewatering fluids differs by more than 5%, in particular more than 10%, preferably more than 15%. The salt content is particularly relevant for moistening the biomass, because the moistening process is intended to wash out, for example, road salt from leaves swept up on streets. A low salt saturation is therefore highly advantageous in the removal of contaminants. This is achieved by the press water separation according to the invention when the press water with the lower salt content is used to moisten the biomass.

[0055] According to one exemplary embodiment, the water used for washing circulates at least partially within the system. It is advantageous both energetically and in terms of water consumption if the water in the washing unit is at least partially integrated into an internal system circuit. This water has the lowest proportion of components originating from cell rupture and is therefore the most fluid. This can, for example, reduce the pumping power required for the water jet cutter.

[0056] According to one exemplary embodiment, washing, storage, and / or conveying further includes gravimetric contaminant separation. For both mechanical dewatering and the reuse of press water in the washing process, it is highly advantageous if the washing unit performs gravimetric contaminant separation. This causes materials heavier than water (e.g., sand, pebbles, metal scrap, etc.) to accumulate at the bottom of a water basin and / or conveying system, allowing for easy disposal. The removal of hard materials, in particular, reduces the dulling, abrasion, and erosion of components in the mechanical dewatering system or the high-pressure pump of the waterjet cutter in the washing unit.

[0057] According to an exemplary embodiment, at least one stream of dewatering fluid is used, at least partially, for washing the biomass (for example, to supply the washing unit and / or the water cutter of the washing unit). This saves fresh water. In particular, the press water can be used to supplement the wash water, which can then be more easily purified and fed to the water cutter system. This dilution with less concentrated water results in a lower viscosity, leading to reduced energy consumption for the water cutter. In particular, fresh water can preferably be supplied to any existing water cutter.

[0058] According to an exemplary embodiment, the ratio of the quantity of the first dewatering fluid stream to the quantity of the second dewatering fluid stream is in the range of 1:1 to 9:1, particularly in the range of 2:1 to 5:1. It has been shown that the operating parameters can be varied surprisingly over a wide range without significantly affecting the fuel quality. Typically, in a two-stage mechanical dewatering process, four times more press water is generated in the first stage than in the second stage. However, to realize the advantages of the invention, the ratios of press water 1 to press water 2 can be in the range of 9:1 to 1:1.

[0059] According to an exemplary embodiment, at least one stream of dewatering fluid, in particular the dewatering fluid with the lower (lowest) COD and / or BOD value, is at least partially suitable for, or is used for, the irrigation and / or fertilization of crops. The production of press waters with different organic content according to the invention results in a fluid with a higher and a fluid with a lower organic load. Simultaneously, the impurity load can also be controlled (e.g., by processing slowly, a very high gravimetric separation (flotation) of heavy and / or hard impurities and contaminants can be achieved). This allows at least one press water stream to be used for fertilizing crops within the applicable regulations. According to an exemplary embodiment, the biomass is moistened before mechanical dewatering, in particular before washing.It can be particularly advantageous if the time interval between wetting and mechanical dewatering is at least 2 minutes, in particular at least 10 minutes, in particular at least 30 minutes, in particular at least 2 hours, and in particular at least 6 hours. This time interval can also be referred to as the wetting contact time. Such a procedure allows, for example, the dissolution (or partial dissolution) of salts in addition to the actual washing process. The dissolution process of salts is also relatively slow, meaning that the throughput through the washing unit is limited by the dissolution time of the salts. If this wetting is carried out more than 10 minutes, more than 30 minutes, more than 2 hours, or even more than 6 hours before washing, various contaminants can dissolve, and the removal of contaminants is optimized.

[0060] According to one exemplary embodiment, a biomass is used which (before washing) has been stored under mechanical pressure for at least one day, at least partially. This can increase the homogeneity of the biomass used, particularly with regard to moisture distribution and / or the degree of microbial decomposition.

[0061] A process according to the invention for producing fuel from pressed biomass can in particular be carried out by means of a system for producing fuel from pressed biomass according to the second aspect explained in more detail below.

[0062] In a second aspect, the present invention relates to a system for producing fuel from compressed biomass. The system may be particularly suitable for carrying out a process for producing fuel from compressed biomass according to the first aspect explained in more detail above. Descriptions of features already given above in connection with the first aspect apply analogously to the same or similar features in connection with the second aspect, even if they are not explicitly repeated.

[0063] The individual components of the system, such as a washing unit, a comminution device, in particular a fine comminution device, a mechanical dewatering device, a drying device, a shaping device (possibly including a compaction device), can in principle correspond to the components as disclosed in the aforementioned literature.

[0064] In connection with the second aspect of the present invention, it is important that the mechanical drainage device (assembly of mechanical drainage devices) is set up (designed, configured) in such a way that at least two streams (mass streams) of drainage fluid with different compositions are formed.

[0065] According to an exemplary embodiment, the mechanical dewatering device has at least two outlets for dewatering fluid (press water). Obtaining different press waters from a single mechanical dewatering device can be based, for example, on the pressure profile inside a screw press: Studies of dewatering processes in the paper industry have shown that the pressure in a suitable screw press increases significantly towards the end of the screw. By providing outlets at different positions on the screw press, press waters with different compositions can be obtained.

[0066] According to an exemplary embodiment, the system comprises at least two mechanical dewatering devices, each with at least one outlet for dewatering fluid (press water). It is advantageous if the at least two mechanical dewatering devices are connected in series (sequentially), i.e., the biomass is first dewatered in a (first) mechanical dewatering device and then in a further (second) mechanical dewatering device, and optionally subsequently in a further (third) mechanical dewatering device.

[0067] According to an exemplary embodiment, the system is designed to produce a fuel output from pressed biomass of more than 50 kg / h, in particular more than 150 kg / h, preferably more than 500 kg / h. It has been shown that the system according to the invention is particularly advantageous in industrial production with higher material throughput, because otherwise, for example, the cooling of the mass flow in the individual subsystems can be too high for some applications.

[0068] According to an exemplary embodiment, the system further comprises a device for increasing the moisture content of the biomass, wherein the device is configured to increase the moisture content of the biomass before the biomass is fed to the mechanical dewatering device. In particular, the system can be designed such that dewatering fluid (press water) from the mechanical dewatering device is fed to the device for increasing the moisture content of the biomass, wherein, in the case of several mechanical dewatering devices, preferably dewatering fluid (press water) from the first mechanical dewatering device is fed to the device for increasing the moisture content of the biomass.

[0069] According to an exemplary embodiment, the system is designed such that at least one stream of dewatering fluid (press water) is at least partially directed to the washing unit. This allows for savings in fresh water. In particular, the press water can be used to supplement the wash water, which can then be more easily purified and supplied to the waterjet cutting system. This dilution with less concentrated water results in a lower viscosity, which in turn reduces the energy consumption of the waterjet cutter.

[0070] According to an exemplary embodiment, the system comprises at least two mechanical drainage devices, which are configured such that different pressing pressures and / or shear forces of more than 10%, in particular more than 15%, preferably more than 20%, are applied between the mechanical drainage devices (for example, in the final stage of drainage). This significantly influences the degree of cell disruption and thus indirectly affects the viscosity of the press water, its CSS / BOD, its impurity content, and / or its salt content. This can be technically controlled, for example, by the shape of the screw and / or its counter-pressing elements.

[0071] According to an exemplary embodiment, the system comprises at least two mechanical dewatering devices, which are designed such that their energy consumption differs by more than 10%, in particular more than 20%, and preferably more than 30% (during normal operation). By suitable measures (for example, by using motor power or frequency converters that control the voltage, speed, torque, and / or current of an asynchronous motor), the energy consumption of at least two mechanical dewatering systems can be varied by more than 10%, in particular more than 20%, and preferably more than 30% during normal operation. This, in turn, directly affects the degree of biomass extraction, which in turn allows for different compositions of the extracted water.

[0072] According to an exemplary embodiment, the system further comprises a separator for metallic, in particular magnetic, materials (foreign substances), which is installed before, in, after, and / or between the mechanical dewatering devices, preferably equipped with an occupancy indicator and / or automatic cleaning. Contamination of biomass with hard metallic foreign substances is often ferrous and therefore magnetic. The use of a magnetic separator protects the mechanical dewatering device(s) and / or the downstream components.

[0073] System components must be protected from damage. It is helpful if the filter has a filter clogging indicator during mechanical cleaning. Even better is a separation system with automatic cleaning. Especially when processing biomass, larger quantities of contaminants (e.g., stones, waste, etc.) are to be expected. These can break a blade of the mowing system while mowing grass or later cause components of the fine shredding unit or even the mechanical dewatering system to break off. Separating metals therefore increases the reliability of the system.

[0074] According to one exemplary embodiment, the system is housed in several individual containments. These containments can be compatible with transport systems and / or offer at least one of the following additional benefits: sound insulation, energy optimization, odor reduction, simplified installation, optimized logistics, and / or simplified transport. The containments can be designed for relatively easy relocation to another site. A typical implementation involves installation in sea freight containers or using containments of compatible dimensions, allowing the individual modules to be easily transported and deployed by truck. These containments can provide additional benefits: 1) Certain areas can be additionally soundproofed. In particular, extensive containment of the functional system components inherently provides sound insulation. 2) The same applies to potential odor emissions.Targeted airflow within the enclosure (possibly with activated carbon filters) reduces potential odor emissions. 3) The enclosure also allows for the collection of waste heat and its targeted use for heat recovery or reuse. 4) Pre-assembly and adjustment of the subsystem components within the enclosure simplifies installation. The components can be pre-leveled on a support frame, so that only the entire frame needs to be leveled during installation, and the subcomponents are automatically aligned. 5) Housing the components in individual subsystems facilitates replacement in case of malfunctions, as a replacement container, for example, only needs to be delivered and connected from a central location, eliminating the need for specialists, especially in remote areas.

[0075] According to an exemplary embodiment, the system further comprises a heat recovery device. The heat recovery device can be configured, in particular, to warm the biomass and / or process water. Preferably, the heat recovery device is configured to support the drying and / or dewatering process. For example, the heat recovery device can be configured to conserve the energy introduced by dewatering in the biomass (storage and / or transport for drying is usually thermally insulated), thus providing preheated biomass for drying that does not need to be heated further by this preheating temperature. Numerous other heat recovery options within the system are possible.For example, the heat from the wastewater heated by the pressing energy can be recovered from the dewatering process.

[0076] According to an exemplary embodiment, the system further comprises one or more storage units configured to store biomass, at least partially, under mechanical pressure for at least one day. This can increase the homogeneity of the biomass used, particularly with regard to moisture distribution and / or the degree of microbial decomposition.

[0077] According to an exemplary embodiment, the system further comprises a device for increasing the moisture content of the biomass, a fine grinding unit, and / or a waterjet cutting subsystem. At least one of these (i.e., the device for increasing the moisture content of the biomass, the fine grinding unit, and / or the waterjet cutting subsystem) preferably has adjustable operating parameters. In particular, it can be advantageous if these operating parameters can be controlled using a data processing system.

[0078] As mentioned previously, the controllability of the two different press water compositions can be influenced and / or controlled by detailed configuration of the mechanical dewatering system. Furthermore, upstream processes can also have an impact. For example, if additional humidification, fine grinding, and / or a water cutter are used to reduce the size of the biomass, the degree of cell disruption before mechanical dewatering can be influenced by the detailed configuration of these subsystems. If, for instance, the mechanical dewatering system remains unchanged, varying the operating parameters of any one of these three subunits can significantly affect the composition of the press water. For example, increasing the moisture content leads to a lower proportion of organic components and / or salts in at least one of the press waters.Furthermore, finer comminution and / or higher intensity (e.g., through higher pressure) of the waterjet cutter leads to greater cell disruption and thus to a change in the composition of the press water, especially the ratios between the different components. Sensor-based (especially near real-time) control and / or regulation of the relevant operating parameters with a data processing system can bring the composition of the press water to a desired value and / or keep it constant.

[0079] In a third aspect, the present invention relates to a computer-readable medium on which a computer program is stored, wherein the computer program is configured such that, when executed on a processor, it controls and / or regulates a method and / or a system for producing fuel from pressed biomass according to the first or second aspect.

[0080] In a fourth aspect, the present invention relates to a program element which is configured such that, when executed on a processor, it controls and / or regulates a method and / or a system for producing fuel from pressed biomass according to the first or second aspect.

[0081] Further considerations and embodiments relating to the present invention include the following:

[0082] Without delving too deeply into the biology of the leaf and the calorific value assessment of the individual components of green waste, the following details should be taken into account:

[0083] Fluid-filled structures (mostly cells) have different shapes and sizes. When considered from the perspective of shear forces acting on a macroscopic or larger scale, long cells containing a large amount of fluid will open at a different time (with a continuous increase in pressure and / or shear force) than others. The same applies to different cell sizes.

[0084] The cuticle (waxy outer layer that reduces water evaporation) must be opened to allow fluid components to leave a significant portion of the leaf. This results in a threshold value regarding the minimum pressure / shear force required for drainage. This means that without a mechanical drainage process with a certain minimum capacity, primarily surface water and external dirt will escape from the green waste.

[0085] By selectively controlling the pressure and / or shear forces, the degree of cell disruption and thus the organic content in the press water can be specifically controlled.

[0086] Further investigations into these relationships have revealed the following surprising details regarding press water extraction and differentiation:

[0087] The more liquid / easily soluble cell components can be removed even at lower energy inputs during mechanical dewatering. This allows for the production of different press waters in multi-stage mechanical dewatering processes or, in larger dewatering systems (e.g., screw presses), the extraction of differentiated press water at an early stage of mechanical compaction / cell disruption through shear forces. The fine comminution achieved by the system according to the invention opens up the green waste material to such an extent that sufficient contact exists between the different liquid components, enabling the relatively energy-efficient leaching of salts (in the presence of water with a low salt content) and the pressing out of fluids with a high water content.

[0088] An increase in water content before the first mechanical dewatering significantly intensifies the leaching effect.

[0089] DETAILED DESCRIPTION OF THE FIGURES Figure 1 is a schematic representation of a system 100 for the production of fuel from pressed biomass according to an exemplary embodiment.

[0090] System 100 for producing fuel from pressed biomass comprises a storage unit 160, an optional feeding device 170, a washing unit 110, a comminution unit 120, which may in particular be a fine comminution unit, a mechanical dewatering unit 130, a drying unit 140, and a shaping unit 150. These components can, in principle, be those described in the literature mentioned above.

[0091] The mechanical drainage device 130 shown in Figure 1, however, differs from the conventional mechanical drainage devices described in the literature. It has two outlets for the drainage fluid or press water formed during mechanical drainage (illustrated by two downward-pointing arrows at different positions on the mechanical drainage device 130 in Figure 1). The two drainage fluids obtained have different compositions.

[0092] The fuel production system 100 shown in Figure 1 further comprises an optional device for increasing the moisture content 166 of the biomass, which is configured (and arranged) to increase the moisture content of the biomass before the biomass is fed to the mechanical dewatering device 130, and an optional heat recovery device 190, which is in particular configured to lead to the heating of the biomass and / or process water and preferably supports the drying and / or dewatering process.

[0093] Figure 2 is a schematic representation of a system 100 for producing fuel from pressed biomass according to a further exemplary embodiment.

[0094] In contrast to the system shown in Figure 1, the system 100 shown in Figure 2 comprises two mechanical dewatering devices 130a, 130b. The two mechanical dewatering devices 130a, 130b are connected in series, so that the biomass first undergoes mechanical dewatering in the first mechanical dewatering device 130a and the dewatering fluid or press water formed is discharged (illustrated by a vertically downward-pointing arrow originating from the first mechanical dewatering device 130a in Figure 2).The biomass, which has already undergone one mechanical dewatering step, is then subjected to a second mechanical dewatering unit 130b for further mechanical sub-drainage, whereby the dewatering fluid or press water formed in this process is also discharged (illustrated by a downward-pointing arrow originating from the second mechanical dewatering unit 130b in Figure 2). The two dewatering fluids have different compositions.

[0095] The present invention has been described with reference to specific embodiments and examples. However, the invention is not limited to these, and various modifications are possible without departing from the scope of the present invention. List of references

[0096] 100 Systems for producing fuel from pressed biomass

[0097] 110 Washing unit 120 Shredding unit

[0098] 130, 130a, 130b mechanical drainage device

[0099] 140 drying equipment

[0100] 150 shaping equipment

[0101] 160 Storage unit 166 Device for increasing humidity

[0102] 170 Feed device

[0103] 190 Heat recovery device

Claims

REQUIREMENTS 1. A process for producing fuel from compressed biomass, the process comprising: Providing biomass; Washing of the biomass; Shredding, especially fine shredding, of biomass; Mechanical dewatering of the biomass; Drying of the biomass; Shaping of the biomass, characterized in that at least two streams of dewatering fluid with different compositions are formed during mechanical dewatering.

2. The method of claim 1, wherein at least a part of the biomass is selected from the group consisting of water hyacinths, seagrass, algae, grass clippings, leaves, green waste and combinations thereof.

3. A method according to any of the preceding claims, wherein at least two streams of dewatering fluid have different viscosities, in particular wherein the stream with the lower viscosity is used to increase the moisture content of the biomass.

4. Method according to one of the preceding claims, wherein at least one stream of drainage fluid is used as process water, for humidification, as fertilizer, for protein production and / or for biogas production.

5. A method according to any of the preceding claims, wherein at least one stream of dewatering fluid is used for biogas production and a mean residence time of the dewatering fluid in a Biogas plant, less than 1 week, especially less than 5 days, preferably less than 3 days.

6. Method according to one of the preceding claims, wherein the biomass has a dry matter content of less than 30%, in particular less than 24%, preferably less than 18% before mechanical dewatering and / or wherein the biomass has a dry matter content of less than 45%, in particular less than 38%, preferably less than 32% before the second mechanical dewatering.

7. Method according to one of the preceding claims, wherein at least one stream of dewatering fluid has a COD and / or BOD value of over 8 g / kg, in particular over 12 g / kg, preferably over 18 g / kg, preferably wherein this stream originates from the last mechanical dewatering before drying.

8. Method according to one of the preceding claims, wherein at least two streams of drainage fluid have a different composition, namely a different proportion of contaminants, a different salt content and / or different COD and / or BOD values.

9. Method according to one of the preceding claims, wherein the method further comprises increasing the moisture content of the biomass before, during and / or after the comminution of the biomass, in particular wherein a first stream of dewatering fluid is used for increasing the moisture content of the biomass.

10. Method according to one of the preceding claims, wherein the method is carried out before drying, in particular before mechanical dewatering, preferably before, during and / or after comminution, furthermore This includes increasing the temperature of the biomass, in particular by heating the biomass using heat recovery.

11. Method according to one of the preceding claims, wherein, in at least two streams of dehydration fluid, the difference in the COD and / or BOD value is more than 1000 mg / kg, in particular more than 2000 mg / kg, preferably more than 4000 mg / kg.

12. Method according to one of the preceding claims, wherein the mean salt content differs by more than 5%, in particular more than 10%, preferably more than 15% in at least two streams of dewatering fluid.

13. Method according to one of the preceding claims, wherein the water used for washing is at least partially circulated within the system.

14. Method according to any of the preceding claims, wherein the washing, storage and / or conveying of the biomass further comprises gravimetric separation of contaminants.

15. Method according to any of the preceding claims, wherein at least one stream of dewatering fluid is used at least partially for washing the biomass.

16. Method according to one of the preceding claims, wherein the ratio of the quantity of the first stream of drainage fluid to the quantity of the second stream of drainage fluid is in the range of 1:1 to 9:

1.

17. Method according to one of the preceding claims, wherein at least one stream of drainage fluid, in particular of the drainage fluid with the lower COD and / or BOD value, at least is partially suitable for the irrigation and / or fertilization of cultivated plants, and is used in particular.

18. Method according to one of the preceding claims, wherein the biomass is moistened before mechanical dewatering, in particular before washing, in particular wherein the time interval between moistening and mechanical dewatering is at least 2 minutes, in particular at least 10 minutes, in particular at least 30 minutes, in particular at least 2 hours, in particular at least 6 hours.

19. Method according to one of the preceding claims, wherein the biomass was stored at least partially under mechanical pressure for at least one day.

20. System (100) for producing fuel from pressed biomass, wherein the system (100) comprises: a washing unit (110); a comminution device (120), in particular a fine comminution device; a mechanical dewatering device (130); a drying device (140); a shaping device (150), characterized in that the mechanical dewatering device (130) is configured to produce at least two streams of dewatering fluid with different compositions.

21. System (100) according to claim 20, wherein the mechanical drainage device (130) has at least two outlets for drainage fluid.

22. System (100) according to claim 20 or claim 21, wherein the system (100) comprises at least two mechanical drainage devices (130a, 130b) each with at least one outlet for drainage fluid, in particular wherein the at least two mechanical drainage devices (130a, 130b) are connected in series.

23. System (100) according to one of claims 20 to 22, wherein the system (100) is designed to have a production quantity of fuel from pressed biomass of more than 50 kg / h, in particular more than 150 kg / h, preferably more than 500 kg / h.

24. System (100) according to any one of claims 20 to 23, wherein the system (100) further comprises a device for increasing the moisture (166) of the biomass, wherein the device is configured to increase the moisture of the biomass before the biomass is fed to the mechanical dewatering device (130), in particular wherein the system (100) is designed such that dewatering fluid from the mechanical dewatering device (130) is fed to the device for increasing the moisture (166) of the biomass, in particular in the case of several mechanical dewatering devices (130a, 130b) dewatering fluid from the first mechanical dewatering device (130) is fed to the device for increasing the moisture (166) of the biomass.

25. System (100) according to one of claims 20 to 24, wherein the system (100) is designed such that at least one stream of drainage fluid is directed at least partially to the washing unit (110).

26. System (100) according to any one of claims 20 to 25, wherein the system (100) comprises at least two mechanical drainage devices (130a, 130b), wherein these are arranged such that there is a difference of more than 10% between the mechanical drainage devices (130a, 130b), in particular more than 15%, preferably more than 20% different pressing pressures and / or shear forces are applied.

27. System (100) according to one of claims 20 to 26, wherein the system (100) comprises at least two mechanical drainage devices (130a, 130b), wherein these are designed such that their energy requirements differ by more than 10%, in particular more than 20%, preferably more than 30%.

28. System (100) according to any one of claims 20 to 27, wherein the system (100) further comprises a separator for metallic, in particular magnetic, materials, which is installed upstream, in, downstream and / or between the mechanical drainage devices (130a, 130b), wherein this is preferably equipped with an occupancy indicator and / or with automatic cleaning.

29. System (100) according to any one of claims 20 to 28, wherein the system (100) is housed in several individual enclosures, in particular wherein these are compatible with transport systems and / or provide at least one of the following additional benefits: sound insulation, energy optimization, odor reduction, installation simplification, logistics optimization and / or transport simplification.

30. System (100) according to one of claims 20 to 29, the system (100) further comprising a heat recovery device (190), in particular wherein the heat recovery device (190) is configured to lead to the heating of the biomass and / or process water, wherein the heat recovery device (190) is preferably configured to support the drying and / or dewatering process.

31. System (100) according to any one of claims 20 to 30, wherein the system (100) further comprises a storage unit (160) configured to store biomass at least partially under mechanical pressure for at least one day.

32. System (100) according to one of claims 20 to 31, wherein the system (100) further comprises a device for increasing the moisture content of the biomass (166), a fine comminution device and / or a water cutting subsystem, in particular that at least one of them has adjustable operating parameters, in particular wherein the operating parameters are controllable using a data processing system.

33. Computer-readable medium on which a computer program is stored, wherein the computer program is configured such that, when executed on a processor, it controls and / or regulates a method according to any one of claims 1 to 19 and / or a system (100) according to any one of claims 20 to 32.

34. Program element which, when executed on a processor, controls and / or regulates a method according to any one of claims 1 to 19 and / or a system (100) according to any one of claims 20 to 32.

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